Steel-Concrete Composite Floor Systems Subject to Fire – Phase 2

This study experimentally investigates the fire-structure interaction and failure mechanisms of steel-concrete composite floor systems commonly used in steel-framed buildings. The full-scale two-story steel gravity frame two bays by three bays in plan are used to mimic the realistic boundary conditions of the 6.1 m x 9.1 m composite floor specimens including beam-end connections and slab continuity to the adjacent bays. To simulate imposed gravity loads during fire in accordance with the current American Society of Civil Engineers (ASCE) 7 standard, the composite floor specimen is hydraulically loaded to 2.7 kPa, and the surrounding (cool) floors were loaded to 1.2 kPa using water-filled drums. The fire test compartment (10 m x 6.9 m x 3.8 m) and four 1 m x 1.5 m natural gas burners (rated 16 MW total) are used to create realistic fire exposure to the composite floor specimen soffit. Over 300 data channels are deployed to measure applied fire and mechanical loading as well as thermal and structural responses at various locations in the two-story building during and after fire exposure.

A total of three compartment fire experiments were conducted to investigate the fire resilience of composite floor systems with a variety of influencing factors including the amount of steel reinforcement in the concrete slab and the passive fire protection scheme for the steel frame in the fire test bay, and the structural loading.

The menu provides access to the completed experiments including the full test report, videos, and data.

• Ramesh, S.; Choe, L.Y.: Structural integrity of composite floors in fire: A comparison of two large-scale experiments with varying slab reinforcement, Fire Safety Journal, Volume 134, 2022.
• Choe, L.Y., Ramesh, S., Hoehler, M.S., Bundy, M.F., Bryant, R., Dai, X.; Story, B., Chakalis, A.; Chernovsky, A.: Fire Resilience of a Steel-Concrete Composite Floor System: Full-Scale Experimental Evaluation for Influence of Slab Reinforcement (Test #2), NIST Technical Note 2203, 2022, 89 pgs.
• Choe, L.Y.; Ramesh, S.; Dai, X.; Hoehler, M.S.; Bundy. M.F.: Experimental study on fire resistance of a full-scale composite floor assembly in a two-story steel framed building, Journal of Structural Fire Engineering, 2021.
• Choe, L.Y., Ramesh, S., Dai, X., Hoehler, M.S., Bundy, M.F., Bryant, R., Story, B., Chakalis, A.; Chernovsky, A.: Fire Resilience of a Steel-Concrete Composite Floor System: Full-Scale Experimental Evaluation for U.S. Prescriptive Approach with a 2-Hour Fire-Resistance Rating (Test #1), NIST Technical Note 2165, 2021, pgs. 176.
• L.Y. Choe, S.Ramesh, C. Zhang, C. Clifton: Behavior of Composite Floor Assemblies Subject to Fire: Influence of Slab Reinforcement, Special Issue: Eurosteel 2021 Sheffield - Steel's coming home, September 9-11, 2021.
• Zhu, Y.; Klegseth, M.; Bao, Y.; Hoehler, M.S.; Choe, L.Y.; Chen, G.: Distributed fiber optic measurements of strain and temperature in long-span composite floor beams with simple shear connections subject to compartment fires, Fire Safety Journal, Volume 121, 2021.
• Fischer, E.; Chicchi, R.; Choe, L.Y.: Review of Research on the Fire Behavior of Simple Shear Connections, Fire Technology, Volumn 57, 2021.

• Choe, L.Y.; Ramesh, S.; Dai, X.; Hoehler, M.S.; Bundy,M.F.: Experimental Study on Fire Resistance of a Full-Scale Composite Floor Assembly in a Two-Story Steel Framed Building, Awarded Best Paper at SiF20 - The 11th International Conference on Structures in Fire, November 30 - December 2, 2020.

• Sauca, A.; Zhang, C.; Grosshandler, W.; Choe, L.Y.; Bundy,M.F.: Development of a Standard Fire Condition for a Large Compartment Floor Assembly, NIST Technical Note 2070, 2019, pgs. 50.
• Zhang, C.; Grosshandler, W.; Sauca, A.; Choe, L.Y.;: Design of an ASTM E119 Fire Environment in a Large Compartment, Fire Technology, 2019.